Method of electrical welding



T. E. MURRAY, 1a.. AND 1. B. MURRAY.

METHOD OF ELECTRICAL WELDING.

APPLICATION FILED MAY 21,, 1019.

Patented Sept. 16, 1919.

UNITED srATEs PATENT onnron.

THOMAS E. MURRAY, JR! AND JOSEPH B. MURRAY, OF BROOKLYN, NEW YORK.

METHOD OF ELECTRICAL WELDING.

Specification of Letters Patent.

Patented Sept. 16, 1919.

application filed May 21, 1919. Serial No. 298,748.

T oall whom it may concern Be it known that we, THOMAS E. MUR- RAY, Jr.,and JOSEPH B. MURRAY, citizens of the United States, residing atBrooklyn, in the county of Kings and State of New York, have invented acertain new and useful Improv'ement in Methods of Electrical Welding, ofwhich the following is a specification. I

The invention is a method of uniting a metal inner tube and a metalouter inclosing tube by a single electrical welding operation.

In the accompanying drawings- Figure 1 is an end view of the weldingelectrodes, the bent plate which finally forms the inner tube, and theouter inclosing tube, the said outer tube being shown in cross section,and the parts being represented in position before welding. Fig. 2 is asimilar view, showing the parts after welding, the inner tube then beingcompleted.

Similar letters of reference indicate like parts.

A and B are the welding electrodes, movable with respect to one anotherby any suitable means, not shown, whereby pressure is exerted upon thejoint during the welding operation. The outer inclosing tube is formedin two longitudinal half sections C, D, preferably produced by strikingup the metal, which are respectively seated in correspondingly formedlongitudinal recesses in said electrodes/ integrally formed w th thesections C, D are take-ups E, F v on section C, and G, H on section D.\Vhen the sections C, D are seated in the recesses of electrodes A, Band before the welding-operation is begun, said take-ups extend into thespace I between said electrodes and reg.

ister, as shown in Fig. 1.

J is a metal plate bent in cylindrical form, with its edges separated bya gap K. "Said bent plate is placed in the section D, the electrode Abeing sufficiently elevated to permit of its introduction.

The electrode A is then forced downward, bringing the edges of thetake-ups into contact, and the welding current is established,

whereby the take-ups become fused as they are. pressed together. As thetake-ups disappear the edges of plate J are forced together. untilfinally the gap K is closed. If it be desired to weld the edges of plateJ, the gap K should be'disposed opposite to the take-ups E and G, asshown in Fig. 1. Part of the fused metal of the take-ups will then enterthe gap K, and part will be extruded to form fins, as shown at L, whichsubsequently may becut ofl. As the gap closes, part of the currentpasses from edge to edge thereof, and so keeps the take-up etal whichentered the gap in a highly he. ted state, while also softening saidedges, thus insuring the joint in the finished tube being producedcoincidently with the welding together of the sections of the outertube, and hence by a single welding operation. The fused metal of thetake-ups which enters gap K bridges the joint betweenthe opposingsurfaces of the inner and outer tubes like a rivet and unites said tubesfirmly together, and also becomes forced into said joint, and so unitessaid tubes over a still larger surface area. Any protrusion of themelted metal into the interior of the inner tube, as indicated at M, mayafterward be cut oil"; or if the inner tube is not to receive some othermemberas would be the case if the inner tube were, for'example, abushingthe protrusion may be left as it is.

We claim:

1. The method of completing a metal inner tube and uniting the same to ametal outer tube inclosing said inner tube, which consists in placing ametal plate bent in tubular form with a gap between its opposing' edgeswithin two' longitudinal half sections of said outer tube, the gap insaid plate being disposed opposite the joint between said sections, thenestablishing the welding current through said sections and pressing thesame together until the edges of said sections and the edges of said gapare welded. 2. The method of closing a metal inner tube and uniting thesame to a metal outer tube, which consists in placing a metal plate bentin tubular form with a gap between its opposing edges withintwo--longitudinal half sections of said outer tube, then establishingthe Welding current through said sections and pressing the same togetheruntil said sections are welded and said gap is closed.

In testimony whereof we ha \-'e affixed our signatures in presence oftwo witnesses.

THOMAS E. MURRAY, JR. JOSEPH B. MURRAY. Witnesses:

GERTRUDE T. PORTER, MAY T. MGGARRY.

